drivers: renesas: rpc: Move to common

Move rpc driver code to common directory, so that the same
code can be re-used by both R-Car Gen3 and RZ/G2 platforms.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Change-Id: I04805d720d95b8edcc14e652f897fadc7f432197
diff --git a/plat/renesas/common/common.mk b/plat/renesas/common/common.mk
index 4603571..b342bdc 100644
--- a/plat/renesas/common/common.mk
+++ b/plat/renesas/common/common.mk
@@ -85,6 +85,7 @@
 			drivers/renesas/common/io/io_memdrv.c		\
 			drivers/renesas/common/io/io_rcar.c		\
 			drivers/renesas/common/auth/auth_mod.c		\
+			drivers/renesas/common/rpc/rpc_driver.c		\
 			drivers/renesas/common/dma/dma_driver.c		\
 			drivers/renesas/common/avs/avs_driver.c		\
 			drivers/renesas/common/delay/micro_delay.c	\